being a guest of my ex-bf's wedding , should i attend?

i have just broken up with my boyfiend for 6 months,and i got a invitation for his wedding yesterday.
looking at the red card ,i felt funny and insinuative.
when we broke up ,my bf said he wanted to be my best friend,because he doesn't want to lose me ,a good girl.at that moment ,i heard my heart breaking.
in fact ,i am a little conflict in my heart ,i want to be there ,and i am afraid of attending this wedding.
i love him ,i want him to get happiness ,but how can i see my lover being other's husband?
i feel sad now ,what should i do?
wedding will be hold next month.

If I were to be in your place, I would have attended the wedding and wish him all the best in his life and happy wedding for both. Once you have given up relationship / friendship, one should not continue to have ill-feelings. Forget and forgive once for all after showing up at the marriage is the best thing.